Rear impact guard

ABSTRACT

A trailer includes front and rear ends spaced in a longitudinal direction to define a cargo area. A frame includes a rear bolster extending in a transverse direction across the rear end below a bottom rear edge of the cargo area. Spaced rear frame posts extend upwardly from respective distal ends of the rear bolster. A rear impact guard includes a bumper extending transversely and spaced below the rear bolster, a pair of outboard posts extending between the bumper and the rear bolster adjacent the respective distal ends of the rear bolster, and at least one inboard post. Each of the outboard posts has a rearward-extending horizontal first flange and an upward-extending vertical second flange spaced forwardly of the first flange, these flanges including multiple apertures aligned with apertures in the trailer frame, each of the apertures accommodating a removable fastener securing the rear impact guard to the trailer frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/464,069, filed Feb. 27, 2017, the entire contents of which areincorporated by reference herein.

BACKGROUND

The invention relates to over-the-road trailers and rear impact guardsthereof. A conventional trailer 1000 is shown in FIG. 18, and isconfigured for over-the-road use with a truck to transport large cargovolumes. The trailer 1000 has a defined front end 1020 adapted forattachment with the truck, and a defined rear end 1040 opposite thefront end 1020. A front-rear, or lengthwise direction X is definedbetween the front and rear ends 1020, 1040. A transverse or lateraldirection Y is defined perpendicular to the lengthwise direction X. Thelengthwise and lateral directions Y are both parallel to a groundsurface along which the trailer 1000 is conveyable. The rear end 1040 inmany cases is provided with doors for accessing the cargo area definedbetween the front and rear ends 1020, 1040 (and between the sidewalls1050 and roof 1060, if so equipped). At the rear end 1040 of thetrailer, a rear impact guard 1100 is provided. The rear impact guard1100 complies with federal mandates for many common types of trailersand is designed to reduce the severity of a crash when a vehiclefollowing the trailer 1000 impacts the rear end 1040 of the trailer1000. The rear impact guard 1100 provides a lowered bumper 1110 belowthe rear sill or rear bolster 1130 at the bottom rear end of the cargoarea. However, it may be desirable to further improve safety, especiallyfor off-center impacts, while minimizing cost and weight penalties tothe trailer.

SUMMARY

In one aspect, the invention provides a trailer having a front endprovided for attachment to a truck, a rear end spaced in a longitudinaldirection from the front end to define a cargo area between the frontand rear ends, and a frame. The frame includes a rear bolster, aplurality of cross-members, and a pair of corner gussets extendingforwardly from respective distal ends of the rear bolster. The rearbolster extends transversely to the longitudinal direction below abottom rear edge of the cargo area. A rear impact guard of the trailerincludes a bumper positioned at the rear end of the trailer and spacedbelow the rear bolster, a pair of outboard posts, and at least oneinboard post. The pair of outboard posts extend between the bumper andthe rear bolster adjacent respective opposed distal ends of the bumper,and the at least one inboard post extends between the bumper and therear bolster at a location laterally between the pair of outboard posts.Each of the pair of outboard posts is provided with a rearward-extendinghorizontal first flange and an upward-extending vertical second flange.Each of the first and second flanges includes multiple apertures alignedwith corresponding apertures provided in the trailer frame, andfasteners are engaged with the apertures of the first and second flangesand the corresponding apertures in the trailer frame to secure theoutboard post to the trailer frame.

In another aspect, the trailer can further include a lateralreinforcement member that is fastened in place with removable fastenersto extend from a first location at a lateral edge of the trailer frameand a second location spaced laterally-inward and rearward of the firstlocation so that the lateral reinforcement member is loaded in tensionupon rear impact of an object with the bumper.

In another aspect, the rear bolster of the trailer can further include alight guard at least partially surrounding at least one tail lightaperture, the light guard providing the apertures corresponding to theapertures in the rearward-extending horizontal first flange of theoutboard post.

In another aspect, the corner gussets can provide the aperturescorresponding to the apertures in the upward-extending vertical secondflange of the outboard post.

In another aspect, the invention provides a rear impact guard kit forconverting an existing trailer rear impact guard, the kit including apair of outboard posts and a plurality of trailer frame reinforcementmembers. Each of the pair of outboard posts is configured to be securedto the trailer frame at a first joint having vertically-extending firstfasteners along a rear edge of the outboard post and at a second jointhaving horizontally-extending second fasteners along a lateral edge ofthe outboard post, forward of the first fasteners.

In another aspect, the invention provides a method of retro-fitting anexisting trailer rear impact guard with the rear impact guard kitincluding the pair of outboard posts and the plurality of trailer framereinforcement members.

In another aspect, the invention provides a trailer having a front endprovided for attachment to a truck and a rear end spaced in alongitudinal direction from the front end to define a cargo area betweenthe front and rear ends. A frame of the trailer includes a rear bolsterextending in a transverse direction across the rear end of the trailerbelow a bottom rear edge of the cargo area, the rear bolster includingat each end a light guard at least partially surrounding at least onetail light aperture formed therein. A pair of spaced rear frame postsextends upwardly from respective distal ends of the rear bolster. A pairof lower rails extends forwardly from respective lower portions of thepair of rear frame posts. Each of a pair of corner gussets is secured inposition to fortify a joint between one of the pair of rear frame postsand a respective one of the pair of lower rails. A rear impact guardincludes a bumper extending transversely and spaced below the rearbolster, a pair of outboard posts extending between the bumper and therear bolster adjacent the respective distal ends of the rear bolster,and at least one inboard post extending between the bumper and the rearbolster at a location between the pair of outboard posts. Each of thepair of outboard posts is secured to the trailer frame with a pluralityof joints, each of the plurality of joints including at least oneremovable fastener. The plurality of joints includes a first jointestablished between a first flange of the outboard post and the lightguard, and a second joint established between a second flange of theoutboard post and the corner gusset.

In another aspect, the invention provides a rear impact guard kit forconverting an existing trailer rear impact guard having a bumper withfree distal ends to a rear impact guard in which the distal bumper endsare secured to a rear bolster of the trailer. The kit includes a pair ofoutboard posts, each of which includes a lower end adapted forsecurement with a respective one of the distal bumper ends and an upperend adapted for securement with a respective distal end of the rearbolster. For each of the pair of outboard posts, there is at least onereinforcement member configured to fortify a joint between a trailerframe rear frame post and a trailer frame lower rail at the distal endof the rear bolster. For each of the pair of outboard posts, there is afirst fastener extending vertically to define a first joint along arearward portion of the upper end of the outboard post. For each of thepair of outboard posts, there is a second fastener extendinghorizontally to define a second joint along a laterally outboard portionof the upper end of the outboard post.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a rear portion of a trailer, including arear impact guard according to one embodiment of the invention.

FIG. 2 is a detail perspective view of a laterally outer portion of thetrailer shown in FIG. 1, including an outboard post.

FIG. 3 is a perspective view of the laterally outer portion of thetrailer of FIG. 2, viewed from underneath the trailer.

FIG. 4 is a perspective view of the laterally outer portion of thetrailer shown in FIG. 2.

FIG. 5 is a perspective view of the laterally outer portion of thetrailer of FIG. 2, viewed from underneath the trailer.

FIG. 6 is a first perspective view of an outboard post of the rearimpact guard of FIGS. 1-5.

FIG. 7 is a second perspective view of the outboard post of FIG. 6.

FIG. 8 is a perspective view of an outboard portion of the trailer frameprior to attachment of the rear impact guard including the outboardposts.

FIG. 9 is a perspective view of an outboard portion of the trailer frameprior to attachment of the rear impact guard including the outboardposts, viewed from underneath the trailer.

FIG. 10 is a perspective view of the rear impact guard of FIGS. 1-5assembled to the trailer frame, as viewed from above.

FIG. 11 is a perspective view of an upper end of one of the outboardposts along with a combined joint between the outboard post, a lateralreinforcement member, and a bottom rail reinforcement member.

FIG. 12 is another perspective view of the combined joint of FIG. 11.

FIG. 13 is a plan view of the laterally outer portion of the rear impactguard.

FIGS. 14 and 15 are perspective views from under the trailer,illustrating bottom rail reinforcement members. Several floorcross-members are removed in FIG. 15.

FIGS. 16 and 17 are perspective views of the bottom rail reinforcementmembers.

FIG. 18 is a perspective view of a trailer, according to the prior art.

DETAILED DESCRIPTION

FIG. 1 illustrates a rear portion of a trailer 100, which in someembodiments can be a trailer configured for over-the-road use with aroad tractor (e.g., in forming a so-called 18-wheeler) to transportlarge amounts of cargo. Aspects of the invention may not be limited tosuch types of trailers however, and it will be understood that featuresdescribed herein may also apply to many other types of trailers,including those typically having rear impact guards, and others that maynot. Similar to the conventional trailer of FIG. 18, the trailer 100 caninclude a chassis having axles with multiple sets of wheels. The trailer100 defines a length in a longitudinal or transport direction betweenits front and rear ends. The length of the trailer 100 can be 53 feet insome constructions, although the trailer 100 can be manufactured toother lengths greater than or less than 53 feet. Perpendicular to thelongitudinal direction, the trailer 100 defines a width and a height.The width cooperates with the length to define a plan view footprint ofthe trailer 100, while the height is measured perpendicular to thefootprint (which can be perpendicular to the ground). Subtracting forwall thicknesses, the length, the width, and the height cooperate todefine a cargo-receiving interior volume of the trailer 100. Theillustrated trailer 100 includes sidewalls, a roof, and a floor,although in other embodiments the trailer only has a floor, or only hasa floor and less than four complete sidewalls. While not shown inentirety, the illustrated trailer 100 is an enclosed trailer, but thetrailer may be a non-enclosed trailer in other constructions. In anyconstruction, the trailer 100 defines a cargo area operable to receive aload of cargo for transport. Longitudinal top rails and longitudinalbottom rails 104 extend along the length of the trailer 100 at thelateral side edges at the tops and bottoms of the lateral sidewalls,respectively. At a rear of the trailer 100 as shown in FIG. 1, anopening is provided to selectively access the cargo area for loading andunloading cargo. One or more doors may be provided to selectively closethe opening. The trailer 100 also has a load floor (not shown) forreceiving and supporting cargo for transport. In some aspects, FIG. 1may illustrate the conventional trailer of FIG. 18 after conversion orretro-fitting with a kit for providing an improved rear impact guard120. As described in further detail with the remainder of the drawings,the rear impact guard 120 can include outboard posts 136 where none wereoriginally present on the conventional trailer of FIG. 18 (i.e., theoriginal rear impact guard of the trailer may include a bumper securedto only one pair of inboard posts such that the distal ends of thebumper are unsupported).

Turning to FIG. 1, two vertically-extending rear frame posts 108 areprovided at the rear end of the trailer 100. The rear frame posts 108define the lateral sides of the opening into the cargo area of thetrailer 100. Along with the longitudinal upper rails, the longitudinalbottom rails 104 terminate at and are secured to the corresponding rearframe posts 108. The rear frame posts 108 can have a hollow boxstructure, or other suitable construction. A rear sill or bolster 128 ofthe trailer frame extends along a bottom rear edge of the cargo area andhas two opposing lateral distal ends secured to (e.g., welded to) thetwo rear frame posts 108. With reference to FIGS. 1-5, 8 and 9, the rearbolster 128 further includes a light guard 129 at least partiallysurrounding one or more tail light apertures 131. The light guard 129projects rearwardly from a rear-facing surface of the rear bolster 128.A lower portion of the light guard 129 extends in a horizontal plane andis provided with a plurality of mounting apertures 133 (FIG. 8). Belowthe load floor, a plurality of spaced-apart cross-members 112 or floorjoists are provided. The cross-members 112 can be spaced at intervalsthroughout the entire length of the trailer 100, each cross-member 112extending along a respective horizontal axis that is transverse to thelongitudinal direction of the trailer 100. A pair oflongitudinally-extending slider rails 116 (one shown in FIGS. 3 and 5)extend underneath the cross-members 112 in the rear section of thetrailer 100. The suspension supporting the wheels of the trailer 100 iscoupled to the slider rails 116, allowing a certain amount of movementof the suspension relative to the slider rails 116. The bottom rails104, the rear frame posts 108, the cross-members 112, and the sliderrails 116, along with additional components described below form a frameof the trailer 100.

Although the frame as described above refers to permanent,originally-supplied components, the frame can be supplemented orreinforced to provide additional strength with a number of “bolt-on”components at the time of installing or converting to the rear impactguard 120 so that retrofitting of existing trailers is made possible viaa “bolt-on” conversion. Although nuts and bolts can be the physicalmechanism by which such a “bolt-on” conversion is provided as shownthroughout the figures, other types of fasteners or joints can be usedin some constructions, and the term “bolt-on” refers to the nature ofthe modification as not requiring substantial permanent modifications,and in particular not requiring any welding in the instant case. Assuch, the rear impact guard 120 and any accompanying supplementalreinforcements can be removed or replaced as needed without destructiveeffects to the permanent components of the trailer frame.

The rear impact guard 120 provided at the rear end of the trailer 100 issecured to the trailer frame, and in particular at least the rearbolster 128 of the frame. The rear impact guard 120 includes a pluralityof elements structurally coupled to the trailer frame below the rearopening of the trailer 100. The rear impact guard 120 can include abumper 124 extending along a horizontal axis A transversely across therear of the trailer 100 at a height spaced below the cargo area. Thebumper 124 can extend parallel and directly below the rear bolster 128.The bumper 124 may take any number of constructions, and may be a hollowbumper tube having a circular, rectangular, or square cross-section,among others. The illustrated bumper 124 is of tubular form, and has amodified square cross-section (when viewed along a transverse directionof the trailer 100, perpendicular to a front-rear direction of thetrailer 100,) with four equal-length sides. The cross-section of thebumper 124 can be consistent throughout its length along an axis A. Inthe illustrated embodiment, the bumper 124 forms the lowest point of therear impact guard 120 and extends across the entire width of the trailer100, or at least within 100 mm of the lateral extremities of the trailer100, although other bumper dimensions are possible. Multiple postssupport the bumper 124 relative to the trailer 100, including at leastone inboard post 132 (e.g., a pair as shown) and a pair of outboardposts 136. In some embodiments, including the illustrated embodiment,the inboard posts 132 are positioned within the central 70 percent ofthe width of the bumper 124, while the outboard posts 136 are positionedat the distal ends of the bumper 124 (e.g., connecting to the bumper 124outside of the central 90 percent or the central 95 percent of the widthof the bumper 124). The inboard posts 132 can be carried over from thepre-existing rear impact guard (e.g., FIG. 18). As such, the inboardposts 132 may not be part of the retro-fit kit that includes the bumper124 and the outboard posts 136. In other constructions, the inboardposts 132 are part of the retro-fit kit, and the inboard posts 132 maybe different from the pre-existing inboard posts in construction and/ormeans of attachment.

Details of the outboard posts 136 are described with respect to one ofthe outboard posts 136 (i.e., driver's side), while it will beunderstood that these features also apply to the other outboard post136, which is formed as a mirror image. The outboard post 136 can beprovided with multiple attachment surfaces at its lower end forattachment to the bumper 124 and multiple attachment surfaces at itsupper end for attachment to the trailer frame (e.g., the rear bolster128 and the corner gusset 148). Between the upper and lower ends of theoutboard post 136, multiple panels are provided, including at least arear panel 140 and a laterally outboard panel 142. The rear panel 140has an outer surface facing the rear of the trailer 100, and thelaterally outboard panel 142 has an outer surface facing laterallyoutward. In some embodiments, such as the illustrated embodiment, thepost 136 further includes a forward panel 144 spaced forwardly of therear panel 140. Although not required among all possible constructions,the three panels 140, 142, 144 can be integrally formed from a singlesheet of material (e.g., bent with two bends) to distinguish the threenon-planar panels 140, 142, 144. Any one or more of the panels 140, 142,144 can include one or more apertures, openings, or cutouts forstrategic weight relief to minimize the overall weight of the post 136and the rear impact guard 120. Non-limiting examples are shown by thetwo apertures provided in the rear panel 140.

As shown in at least FIGS. 3 and 5-7, the outboard post 136 can furtherinclude a horizontal cap or gusset 145 positioned at the upper portionand secured (e.g., via welding, folding of material common to any or allof the panels 140, 142, 144, and the like) with the panels 140, 142, 144to further strengthen the post and provide a mounting location asdiscussed below. The gusset 145 can be provided in plate or sheet formand may include at least one aperture for strategic weight relief, oneexample of which is shown in the drawings. The upper horizontally-lyingsurface of the gusset 145 may abut corresponding bottom ends of any orall of the rear bolster 128, the rear frame post 108, and the cornergusset 148. In the illustrated construction, a shim plate 161 isprovided atop the gusset 145 at the rearward end adjacent the rear panel140 of the outboard post 136 as shown in at least FIGS. 6, 7 and 11. Theshim plate 161 has a thickness equal to a height difference by which therear frame post 108 extends downwardly past the bottom of the rearbolster 128 (e.g., a return flange 128A of the rear bolster 128). Thus,the outboard post 136 as a whole can abut the bottom end of the rearframe post 108 and the bottom of the rear bolster 128 simultaneously.The shim plate 161 can be welded to the gusset 145. The shim plate 161and the gusset 145 have mounting apertures for fasteners 163 that areprovided to extend vertically and secure the gusset 145 to the returnflange 128A of the rear bolster 128 as shown in FIG. 3.

At a lower end, the outboard post 136 is provided with apertures forfastening to a mounting bracket 246 provided on the bumper 124. Theoutboard post 136 can be provided with at least one aperture in each oneof the panels 140, 142, 144, and the mounting bracket 246 has aperturescorresponding to the apertures in each panel 140, 142, 144. The outboardpost 136 is secured to the mounting bracket 246 solely with a pluralityof threaded fasteners 165 as shown in FIGS. 1-7. In other constructions,the bumper 124 can be integrally provided (e.g., welded) with theoutboard posts 136 rather than removably fastened, and in otherconstructions still the bumper 124 can be removably fastened bystructures and fasteners other than those expressly shown and describedherein.

As shown in FIGS. 1-5, the rear frame post 108 extends lower than thebottom rail 104. A corner gusset 148 of the trailer frame is secured tothe rear frame post 108, and the bottom rail 104 and/or at least one ofthe cross-members 112 to occupy the space forward of the bottom end ofthe rear frame post 108 and below the rear end of the bottom rail 104.As described below, the corner gusset 148 provides a mounting locationfor attachment of the outboard post 136 to mount the rear impact guard120 to the trailer 100. Due to the fact that the rear impact guard 120is coupled to the trailer frame at the corner gusset 148 as described infurther detail below, an increase in loading of the area of the trailerframe including the corner gusset 148 during a rear impact can beexpected compared to a rear impact guard with no outboard posts, andadditional reinforcement may be provided to the bottom rail 104immediately adjacent the corner gusset 148.

In some embodiments, such as in the illustrated embodiment, one or morereinforcement members 170, 172 (FIGS. 5 and 10-17) extend directlyforward from the corner gusset 148 along a portion of the bottom rail104 (e.g., alongside at least a bottom portion of the bottom rail 104and directly alongside an inboard face thereof). These reinforcementmembers 170, 172 are illustrated and described primarily with respect tothe driver's side of the rear impact guard 120 and correspondingoutboard post 136, while it will be understood that these features alsoapply to another corresponding set on the other lateral side, which areformed in mirror images from those shown in detail. A first or primaryreinforcement member 170 has a portion (e.g., of triangular shape inside view) that extends below a bottom edge of the bottom rail 104. Theillustrated primary reinforcement member 170 has a triangular sideprofile that tapers in height toward the forward end, although othershapes are possible while still being attached to the other portions ofthe trailer frame described below. The rearward end of the primaryreinforcement member 170 can be positioned on a forward end of thegusset 145 at the upper end of the outboard post 136. With referenceagain to the illustrated embodiment, in some embodiments the height atthe rear end of the primary reinforcement member 170 matches that of thecorner gusset 148. The secondary reinforcement member 172 can bepositioned forward of the primary reinforcement member 170, and isprovided with a size and shape that fits between two adjacentcross-members 112. The secondary reinforcement member 172 can beentirely nested between the cross-members 112, with no gusset portionextending below the cross-members 112 or the bottom rail 104. Thesecondary reinforcement member 172 provides a reinforced connectionbetween the two adjacent cross-members 112, alongside the bottom rail104. Each of the primary and secondary reinforcement members 170, 172,which are shown separately from the remaining structures in FIGS. 16 and17, can have an L-shaped cross-section.

The primary reinforcement member 170 features recesses 174 that receivethe ends of the cross-members 112 as shown in FIG. 5 so that the primaryreinforcement member 170 form-fits around one or more of thecross-members 112. The design of the reinforcement members 170, 172allows retrofitting an existing trailer 100 in which all thecross-members 112 are provided with equal length, and does not requiremodification of removal of the cross-members 112 since the reinforcementmembers 170, 172 are not sandwiched between the bottom rail 104 and theends of the cross-members 112. The primary reinforcement member 170 canbe provided with mounting holes to be secured with fasteners to thebottom rail 104.

As shown in FIGS. 5 and 10-17, a flange or gusset 160 perpendicular toboth portions of the L-shaped primary reinforcement member 170 isprovided at the rearward end of the primary reinforcement member 170.The gusset 160 is formed as a sheet or plate that extends in a verticaldirection and transverse to the longitudinal direction of the trailer100. The gusset 160 includes at least one mounting aperture forreceiving a fastener 171. In the illustrated construction, the gusset160 includes two vertically-spaced mounting apertures configured toreceive two fasteners 171 (e.g., bolts) so that the fasteners extendhorizontally. The mounting apertures are configured to receive thefasteners 171 so that the fasteners extend parallel to the longitudinaldirection of the trailer 100. The fastened joint provided by the gusset160 and the corresponding fasteners can be a combination joint with theoutboard post 136 and at least one additional reinforcement member 180as described in further detail below. However, a detailed description ofthe structure of the outboard post 136 is first provided.

The outboard post 136 has an upper portion that wraps around the lowerrear corner of the trailer frame to connect to the trailer framedirectly inboard of the rear frame post 108 and directly forward of therear frame post 108. As such, a lower end of the rear frame post 108nests into a recess 109 formed by the upper end of the outboard post 136as shown in FIGS. 2, 6, and 7. With continued reference to the outboardpost 136 of the illustrated embodiment shown in FIGS. 6 and 7, arearward-extending horizontal first flange is formed at the upper end ofthe rear panel 140. The first flange can be defined as two overlaidsheet or plate sections, a first 147 of which can be provided as anintegral extension of the rear panel 140 and a second 150 of which canbe permanently secured (e.g., by welding) to a rear face of the rearpanel 140. As shown, the second plate section 150 can be part of aU-shaped bracket or gusset that is welded to the rear face of the rearpanel 140 at its upper end. Although providing multiple overlaid platesections increases the strength of a fastener joint made at the firstflange, in other constructions, the first flange can be provided by asingle plate section having a suitable thickness. The first flangeprovided by the first and second plate sections 147, 150 can bepositioned directly adjacent (e.g., below) a horizontal plate or flangeof the rear bolster 128 to be secured with fasteners 153 thereto. Forexample in the illustrated construction, the horizontal lower portion ofthe light guard 129 is utilized so that mounting apertures provided inthe first flange align with the apertures 133 in the light guard 129 anda plurality of laterally-spaced fasteners 153 extend therethrough tofasten the joint. The fasteners 153 are arranged to extend verticallythrough the first flange and the horizontal lower portion of the lightguard 129. The fasteners 153 are arranged to be stressed primarily intension upon a rear impact to the bumper 124. In other constructions(e.g., those without a light guard 129), the first flange can be securedwith another horizontal flange or wall of the rear bolster 128.

The upper end of the outboard post 136 further includes anupward-extending vertical second flange 155. The second flange 155 canbe formed of a sheet or plate that defines a vertical plane,perpendicular to a horizontal plane defined by the gusset 145 and thehorizontal plane defined by the plate sections 147, 150 of the firstflange. The second flange 155 can be a bent sheet portion formedintegrally with the gusset 145. The second flange 155 includes multipleapertures aligned with corresponding apertures provided in the trailerframe, and fasteners 157 are engaged with the apertures of the secondflange 155 and the corresponding apertures in the trailer frame tosecure the outboard post 136 to the trailer frame. In particular, thesecond flange 155 is arranged alongside a laterally outboard surface ofthe corner gusset 148 and is fastened to the corner gusset 148 (e.g.,with two fasteners 157). Each of the fasteners 157 joining the secondflange 155 and the corner gusset 148 are arranged to extend horizontallyand in a direction transverse to the longitudinal direction of thetrailer 100. The fasteners 157 are arranged to be stressed primarily inshear upon a rear impact to the bumper 124.

As shown in at least FIGS. 6, 7, 11, and 12, the outboard post 136 caninclude additional vertical gussets at its upper end between thehorizontal gusset 145 and the vertical second flange 155. These caninclude a first vertical gusset 167 at the forwardmost end and a secondvertical gusset 169 spaced rearwardly from the first vertical gusset167. Each of the first and second vertical gussets 167, 169 can bewelded in place (e.g., welded partially or fully along seams with boththe gusset 145 and the second flange 155). The second vertical gusset169 may have a reduced vertical height compared to the first verticalgusset 167 as shown. While both the vertical gussets 167, 169 provideadditional strength to the upper end of the outboard post 136, the firstvertical gusset 167 is further utilized to make a combined joint, or inparticular a three-member joint using at least one fastener 171 thatextends horizontally and parallel to the longitudinal direction of thetrailer 100. Secured by the fasteners 171 are three stacked materialsheets, including the first vertical gusset 167 at the forward end ofthe outboard post 136, the gusset 160 at the rearward end of the primaryreinforcement member 170, and an end flange of a lateral reinforcementmember 180 or “cross brace”, all of which have corresponding alignedapertures to receive the fasteners 171. The lateral reinforcement member180 extends from its first end at the aforementioned joint to a secondend that is spaced in a direction laterally inboard and rearward of thefirst end. The second end of the lateral reinforcement member 180 can besecured to any available structural member of the trailer frame. In theillustrated construction, the lateral reinforcement member 180 iscoupled with fasteners at a joint where the upper end of the inboardpost 132 joins the slider rail 116 beneath the trailer floor. Thelateral reinforcement member 180 is loaded in tension upon rear impactupon the bumper 124. Thus, the lateral reinforcement member 180 can beprovided by a rigid member such as a sheet, a bar, a plate or a tube ofmaterial (e.g., steel) or alternately by a non-rigid member such as achain, a cable, etc. The lateral reinforcement member 180 reinforces thelower corner of the trailer frame to inhibit rolling or folding overduring a rear impact where loads are transferred to the lower corner ofthe trailer frame from the outboard posts 136.

By designing the outboard posts 136 of the rear impact guard 120 and thereinforcement members (i.e., the primary and secondary reinforcementmembers 170, 172 for the bottom rail 104 and the lateral reinforcementmembers 180) to be bolted onto the trailer frame, the rear impact guard120 as a whole and/or components thereof may be simply retrofittedwithout welding or removing existing components. For example, the cornergussets 148 of the trailer 100 may be welded in place at the time oforiginal manufacture (e.g., in producing the pre-existing trailer 1000of FIG. 18). The rear impact guard 120 does not modify, remove, orreplace the existing corner gussets 148, but rather reinforces them withadditional components to complement the added strength provided by theaddition of the outboard posts 136, which allow much greater rear impactloads to be transferred to the outer corners of the trailer frame. Therear impact guard 120 is also made serviceable in the field with minimaltime and cost, and minimal risk of damaging the trailer 100. Forexample, in the event of cosmetic or minimal damage to an outboard post136 or to the bumper 124, the individual component (or the rear impactguard 120 as a whole) may be removed by simply removing boltedconnections, and can then be replaced. Although bolts and nuts may beutilized throughout the rear impact guard 120 as shown and described, itwill be understood that other types of threaded fasteners may instead beutilized, as can any other type of removable fastener. In this regard,as used herein the term “bolt-on” shall not be interpreted as limitingspecifically to the use of bolts. The removable fasteners used at thevarious joints joining the rear impact guard 120 to the can trailerframe can include fasteners adapted for non-destructive removal andre-use (i.e., multi-use or reusable fasteners) as opposed to single-usefasteners. In some constructions, the rear impact guard 120 is attachedto the trailer frame entirely without any permanent securements, such aswelds.

The embodiments described above and illustrated in the figures arepresented by way of example only and are not intended as a limitationupon the concepts and principles of the present invention. As such, itwill be appreciated by one having ordinary skill in the art that variouschanges in the elements and their configuration and arrangement arepossible without departing from the spirit and scope of the presentinvention. For example, one having ordinary skill in the art willappreciate that specific features of the numerous embodiments disclosedmay be mixed and matched in other ways where not specifically inhibited,even though specific illustration of such embodiments may not beexhaustively covered herein.

What is claimed is:
 1. A trailer comprising: a front end provided forattachment to a truck; a rear end spaced in a longitudinal directionfrom the front end to define a cargo area between the front and rearends; a frame, the frame including a rear bolster extending in atransverse direction across the rear end of the trailer below a bottomrear edge of the cargo area, and a pair of spaced rear frame postsextending upwardly from respective distal ends of the rear bolster; anda rear impact guard including a bumper extending transversely and spacedbelow the rear bolster, a pair of outboard posts extending between thebumper and the rear bolster adjacent the respective distal ends of therear bolster, and at least one inboard post extending between the bumperand the rear bolster at a location between the pair of outboard posts,wherein each of the pair of outboard posts is provided with arearward-extending horizontal first flange and an upward-extendingvertical second flange spaced forwardly of the horizontal first flange,each of the first and second flanges including multiple aperturesaligned with corresponding apertures provided in the trailer frame, eachof the multiple apertures accommodating a removable fastener securingthe rear impact guard to the trailer frame at a respective one of thefirst and second flanges.
 2. The trailer of claim 1, wherein each of thepair of outboard posts is formed as an open cross-section profile frommultiple panels that extend between upper and lower ends of the outboardpost, and wherein a top gusset extends between the multiple panels, thetop gusset positioned to support the rear bolster from below.
 3. Thetrailer of claim 2, wherein at least one additional removable fasteneris provided to extend through and securely join the top gusset with therear bolster.
 4. The trailer of claim 1, wherein the trailer framefurther includes a pair of corner gussets, each of which is secured inposition to fortify a joint between a bottom end of one of the pair ofrear frame posts and a respective lower rail of the trailer frameextending forwardly from the rear frame post, and wherein the secondflange of each outboard post overlies the respective corner gusset inside view so that the multiple apertures of the second flange arealigned with corresponding apertures formed in the corner gusset and thecorresponding removable fasteners extend through the second flange andthe corner gusset to secure the rear impact guard to the trailer frame.5. The trailer of claim 1, further including a pair of lateralreinforcement members, each of which is fastened in place with removablefasteners to extend from a first location at a respective lateral edgeof the trailer frame and a second location spaced laterally-inward andrearward of the first location so that the lateral reinforcement memberis loaded in tension upon rear impact of an object with the bumper atthe respective outboard post.
 6. The trailer of claim 1, wherein therear bolster further includes a light guard at least partiallysurrounding at least one tail light aperture formed therein, the lightguard providing the apertures corresponding to the apertures in therearward-extending horizontal first flange of each of the pair ofoutboard posts.
 7. The trailer of claim 1, wherein the trailer framefurther includes a plurality of cross-members extending transversely atintervals spaced forwardly of the rear bolster.
 8. The trailer of claim1, wherein the horizontal first flange of each of the pair of outboardposts is laterally spaced from the adjacent one of the pair of rearframe posts, and positioned vertically above a bottom end thereof. 9.The trailer of claim 1, wherein each of the pair of outboard postsincludes a plurality of panels that extend between upper and lower endsof the outboard post, and wherein the horizontal first flange has aforwardmost edge terminating at a rearmost surface of a rearmost one ofthe plurality of panels.
 10. The trailer of claim 9, wherein thehorizontal first flange of each of the pair of outboard posts is formedat least in part by an upper portion of a U-shaped bracket.
 11. Thetrailer of claim 1, wherein the pair of outboard posts and the at leastone inboard post are secured to the trailer frame exclusively withremovable fasteners.
 12. A trailer comprising: a front end provided forattachment to a truck; a rear end spaced in a longitudinal directionfrom the front end to define a cargo area between the front and rearends; a frame, the frame including a rear bolster extending in atransverse direction across the rear end of the trailer below a bottomrear edge of the cargo area, the rear bolster including at each end alight guard at least partially surrounding at least one tail lightaperture formed therein, a pair of spaced rear frame posts extendingupwardly from respective distal ends of the rear bolster, a pair oflower rails extending forwardly from respective lower portions of thepair of rear frame posts, and a pair of corner gussets, each of which issecured in position to fortify a joint between one of the pair of rearframe posts and a respective one of the pair of lower rails; and a rearimpact guard including a bumper extending transversely and spaced belowthe rear bolster, a pair of outboard posts extending between the bumperand the rear bolster adjacent the respective distal ends of the rearbolster, and at least one inboard post extending between the bumper andthe rear bolster at a location between the pair of outboard posts,wherein each of the pair of outboard posts is secured to the trailerframe with a plurality of joints, each of the plurality of jointsincluding at least one removable fastener, the plurality of jointsincluding a first joint established between a first flange of theoutboard post and the light guard, and a second joint establishedbetween a second flange of the outboard post and the corner gusset. 13.The trailer of claim 12, wherein the first flange is arearward-extending horizontal flange, and the second flange is anupward-extending vertical flange spaced forwardly of the horizontalfirst flange.
 14. The trailer of claim 12, wherein each of the pair ofoutboard posts includes a plurality of panels that extend between upperand lower ends of the outboard post, and wherein the horizontal firstflange has a forwardmost edge terminating at a rearmost surface of arearmost one of the plurality of panels.
 15. The trailer of claim 14,wherein the horizontal first flange of each of the pair of outboardposts is formed at least in part by an upper portion of a U-shapedbracket.
 16. The trailer of claim 12, wherein the plurality of joints ofeach of the pair of outboard posts includes a third joint establishedbetween the trailer frame and a top gusset of the outboard post thatsupports one or both of the rear frame post and the rear bolster frombelow.
 17. The trailer of claim 16, wherein each of the first, second,and third joints includes multiple removable fasteners.
 18. The trailerof claim 16, wherein all of the removable fasteners of the first,second, and third joints are reusable fasteners.
 19. The trailer ofclaim 12, further including a pair of lateral reinforcement members,each of which is fastened in place with removable fasteners to extendfrom a first location at a respective lateral edge of the trailer frameand a second location spaced laterally-inward and rearward of the firstlocation so that the lateral reinforcement member is loaded in tensionupon rear impact of an object with the bumper at the respective outboardpost.
 20. The trailer of claim 12, wherein the trailer frame furtherincludes a plurality of cross-members extending transversely atintervals spaced forwardly of the rear bolster.
 21. The trailer ofclaim, 12 wherein the first joint is laterally spaced from the adjacentone of the pair of rear frame posts, and positioned vertically above abottom end thereof.
 22. The trailer of claim 12, wherein the pair ofoutboard posts and the at least one inboard post are secured to thetrailer frame exclusively with removable fasteners.
 23. A rear impactguard kit for converting an existing trailer rear impact guard having abumper with free distal ends to a rear impact guard in which the distalbumper ends are secured to a rear bolster of the trailer, the kitcomprising: a pair of outboard posts, each of which includes a lower endadapted for securement with a respective one of the distal bumper endsand an upper end adapted for securement with a respective distal end ofthe rear bolster; for each of the pair of outboard posts, at least onereinforcement member configured to fortify a joint between a trailerframe rear frame post and a trailer frame lower rail at the distal endof the rear bolster; for each of the pair of outboard posts, a firstfastener extending vertically to define a first joint along a rearwardportion of the upper end of the outboard post; and for each of the pairof outboard posts, a second fastener extending horizontally to define asecond joint along a laterally outboard portion of the upper end of theoutboard post.